Fire door

ABSTRACT

Improved fire door assemblies comprise a door frame having structural elements defining an opening, and a door sized to fit into the frame and occlude the opening. Generally, the door can further comprise a top member, a first layer of insulation material positioned along a bottom surface of the door and a support structure connected to the first layer of insulation material. Due to the design of the support structure and the first insulation layer, direct contact between the support structure and the door frame is reduced or eliminated, which can reduce heat transfer pathways between the door frame and the door. In some embodiments, a second insulation layer can be oriented towards the top surface of the door. In these embodiments, the support structure can hold the first insulation layer in a fixed position relative to the second layer of insulation material such that a gap is located between the first layer of insulation material and the second layer of insulation material.

FIELD OF THE INVENTION

The present invention relates to fire door assemblies comprising a doorframe and an associated fire door. In particular, the invention relatesto a fire door having a support structure connected to a layer ofinsulating material which reduces the transfer of heat between the frameand the support structure.

BACKGROUND OF THE INVENTION

Numerous building codes have been enacted by federal, state and localgovernments to promote public safety. In particular, some of theseregulations require fire resistant structures and materials such as, forexample, panels, insulation and the like to be installed in thebuildings to reduce the spread of heat and fire. Generally, multi-storybuildings have openings between floors to provide access and/orventilation between floors. These openings can be used to access crawlspaces, transport equipment between floors and the like. However, suchopenings can pose a safety hazard in the event of a fire, since theseopenings provide a pathway for fire to spread to adjacent floors.Consequently, building regulations typically require these openings tobe occluded with fire resistant materials.

One way of occluding the openings between floors in multi-storybuildings is to install fire doors that are designed to prevent thespread of heat and fire between adjacent floors. The door can be openedto provide access between floors through the opening and closed to blockthe opening, for example, to resist the spread of fire. In someembodiments, the fire doors have structure which holds the door in anopen position, and can further comprise a heat sensitive closingmechanism which automatically closes the door in the event of a fire.

NFPA 288 provides an industry standard for obtaining a temperaturerating on a fire door based on a maximum desired temperature on anunexposed surface away from direct exposure to the fire to prevent theeffect of a fire from the floor below from causing damage to the floorabove. The NFPA 288 procedure is incorporated herein by reference.Generally, some form of insulation is required to achieve a satisfactoryrating under the NFPA 288 procedure. However, fire doors are generallycomposed of metal, and therefore can contain metal to metal contactsthat provide heat transfer pathways between, for example, the bottomsurface of the door and the top surface of the door. These heat transferpathways can increase the temperature on the top surface of the door,which can lower the fire rating of the door and/or increase the amountof insulation required to achieve a particular fire rating.

SUMMARY OF THE INVENTION

In a first aspect, the invention pertains to a fire resistant doorcomprising a door frame having structural elements defining an openingand a door sized to fit into the frame and occlude the opening. In theseembodiments, the door can comprise a top member configured to have aselected orientation in a closed configuration with the door engagingthe frame and a first layer of insulation material positioned along thebottom surface of the door. Additionally, the door can further comprisea support structure connected to the first layer of insulation materialto hold the first layer of insulation in a fixed position that is spacedapart relative to the top member, wherein the first layer of insulationmaterial engages the frame in the closed configuration without anycontact between the support structure and the frame.

In another aspect, the invention pertains to a fire resistant doorcomprising a door frame having structural elements defining an openingand a door sized to fit into the frame and occlude the opening, the doorhaving a top surface and a bottom surface. In these embodiments, thedoor can comprise a first layer of insulation material oriented towardsthe bottom surface of the door and a second layer of insulation materialoriented towards the top surface of the door. Additionally, the door canfurther comprise a support structure connected to the first layer ofinsulation material to hold the first layer of insulation material in afixed position relative to the second layer of insulation material suchthat a gap exists between the first layer of insulation material and thesecond layer of insulation material.

In a further aspect, the invention pertains to a method of preventingthe spread of fire through an opening. In these embodiments, the methodcomprises providing a fire door assembly sized to occlude the opening,wherein the fire door assembly comprises a door frame and a door, andwherein the door comprises a first layer of insulation materialconnected to a support structure such that the no contact exists betweenthe support structure and the frame when the door is in a closedconfiguration. In some embodiments, the method can further comprisemoving the door from an open configuration to a closed configuration inresponse to a fire.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a fire door assembly comprising a frameand a door, wherein the door is in an open configuration relative to theframe with structure being displayed as transparent to show hiddenstructure;

FIG. 2 is a side view of the fire door assembly of FIG. 1, wherein thedoor is in an open configuration relative to the frame with structurebeing displayed as transparent to show hidden structure;

FIG. 3 is a cross-sectional view of the fire door assembly of FIG. 1,wherein the door is in a closed configuration relative to the frame,with the cross section taken through a plane generally along the extentof the door and frame;

FIG. 4 is a perspective view of a fire door showing an angle structureconnected to a support member; and

FIG. 5 is a perspective view of the fire door of FIG. 4 having circlesindicating the points of contact between the angle structure and thesupport member.

DETAILED DESCRIPTION OF THE INVENTION

Improved fire door assemblies comprise a door frame having structuralelements defining an opening, and a door sized to fit into the frame andocclude the opening. Generally, the door can further comprise a topmember, a first layer of insulation material positioned along a bottomsurface of the door and a support structure connected to the first layerof insulation material. Due to the design of the support structure andthe first insulation layer, direct contact between the support structureand the door frame is reduced or eliminated, which can reduce heattransfer pathways between the door frame and the door. In oneembodiment, the support structure can comprise a support memberconnected to angle structure, wherein the first layer of insulatingmaterial is connected to the angle structure. The angle structure canprovide a surface for connecting the first layer of insulating materialto the support structure. In some embodiments, a second insulation layercan be oriented towards the top surface of the door. In theseembodiments, the support structure can hold the first insulation layerin a fixed position relative to the second layer of insulation materialsuch that a gap is located between the first layer of insulationmaterial and the second layer of insulation material. The first andsecond layers of insulation material, along with the gap between the twolayers, can reduce the heat transfer between the bottom surface of thedoor and the top surface of the door. Generally, the door and the doorframe can comprise metal such as, for example, aluminum.

As described above, fire doors can be used to occlude openings betweenfloors of, for example, multi-story buildings. To achieve a satisfactoryNFPA 288 and/or ASTM-E119 rating, fire doors have employed a layer ofinsulation such as, for example, mineral wool or fiber board, and/orhave coated the door with a layer of intumescent material. Generally,intumescent material swells or puffs up to a relatively thick cellularfoam char in response to heat. However, both the door and the door frameof known fire door assemblies are composed of metal, which can createmetal to metal contacts between the frame and the door. These metal tometal contacts can create a heat flow paths between the frame and thedoor, which facilitates the transfer of heat from the bottom surface ofthe door to the top surface of the door. Since the fire doors aredesigned to prevent the spread of heat and fire between, for example,adjacent floors of a building, it is undesirable to have heat flowpathways between the bottom surface of the door and the top surface ofthe door. As described herein, one way of reducing the heat flowpathways between the bottom surface of the door and the top surface isto employ a door comprising a support structure connected to a firstlayer of insulation material such that direct contact between thesupport structure and the frame is eliminated. This contact is replacedwith contact between an insulating member integrated into the door andthe door frame. Additionally, heat flow from the bottom surface to thetop surface can be reduced by employing a first layer of insulationmaterial and a second layer of insulation material, wherein a gap isprovided between the first layer of insulation material and the secondlayer of insulation material.

In some embodiment, the fire door generally comprises a top surface, afirst layer of insulation oriented towards the bottom surface of thedoor and a support structure connected to the first layer of insulationmaterial. Generally, the support structure holds the first layer ofinsulation in a fixed position relative to the top member. In someembodiments, the support structure can hold the first layer ofinsulation material such that the first layer of insulation materialengages the door frame in the closed configuration without any contactbetween the support structure and the frame with the first layer ofinsulation forming the exposed bottom surface of the door. Thus, sincethe support structure does not directly contact the door frame, heattransfer from the frame through the support structure to the top surfaceof the door can be reduced. In some embodiments, the support structurecan comprise a support member connected to the top member of the doorand an angle structure connected to the support member. In oneembodiment, only six points of contact exist between the angle structureand the support member, which reduces heat transfer through the supportstructure to the top surface of the door.

As described above, in some embodiments the fire door can furthercomprise a second layer of insulation material oriented towards a topsurface of the door. In these embodiments, a support structure can holdand position the first layer of insulation material in a fixed positionrelative to the second layer of insulation material such that a gapexists between the first layer of insulation material and the secondlayer of insulation material. The first and second layer of insulation,along with the gap between the two layers, can reduce the heat transferfrom the bottom surface of the door to the top surface of the door. Insome embodiments, the first layer of insulating material can comprise aplurality of layers of an endothermic blanket material coupled togetherto form a composite structure, while the second layer of insulatingmaterial can comprise, for example, a non-woven mineral fiber material.In other embodiments, the first layer of insulation material and thesecond layer of insulation material can comprise the same type ofinsulation.

A fire door assembly incorporating desired features of the improved doorand frame is depicted in FIGS. 1-3. Referring to FIGS. 1-3, a fire doorassembly 100 is shown comprising door frame 102 and door 104. In someembodiments, door 104 can be pivotally coupled to frame 102 by one ormore hinges 105 such that door 104 can be moved from an open position toa closed position through rotation of the hinges. However, otherembodiments exist where door 104 is not pivotally coupled to frame 102.In these embodiments, door 104 can be provided with a plurality ofhandles, which facilitates manually inserting and removing door 104 fromframe 102. As shown in FIG. 1, frame 102 can comprise a plurality ofstructural elements 106 which define an opening 108. Frame 102 can beprovided with an external flange 107, which facilitates engagement ofdoor frame 102 with a surface such as, for example, a floor. Generally,door 104 can comprise top member 110, support structure 112 and firstinsulation layer 114. In some embodiments, top member 110 defines a topsurface 111 of door 104. As discussed below, support structure 112 canbe connected to first insulation layer 114 such that the firstinsulation layer 114 can be held in a fixed position relative to topmember 110. Additionally, as shown in FIG. 3, door 104 can comprise asecond layer of insulation material 122 oriented towards top member 110.In some embodiments, support structure 112 can hold first layer ofinsulation material 114 in a fixed position relative to second layer ofinsulation material 122 such that a gap 124 exists between the firstlayer of insulation material 114 and the second layer of insulationmaterial 122.

Door 104 can further comprise a heat activated self-closing mechanism118 which functions to move door 104 from an open configuration (shownin FIG. 1) into a closed configuration (shown in FIG. 3) in the event ofa fire. In some embodiments, heat activated self-closing mechanism 118can comprise collapsible supporting member 120 and a trigger mechanism.Generally, collapsible supporting member 120 holds the door in the openconfiguration. In the event of a fire, the trigger mechanism caninteract with the collapsible supporting member 120 to move door 104into the closed configuration. Additional description of self closingmechanisms suitable for use in fire door assemblies can be found in U.S.Pat. No. 6,615,544 to Tlemcani et al., entitled “Fire-Resistant Door,”which is hereby incorporated by reference herein.

As described above, frame 102 can comprises a plurality of structuralelements 106 which define opening 108. In some embodiments, frame 102can have a rectangular cross-section, however, one of ordinary skill inthe art will recognize that no particular cross-sectional shape of frame102 is required by the present disclosure. Additionally, the size offrame 102, and of opening 108, can be guided by the intended applicationof a particular fire door assembly. Referring to FIG. 1, frame 102 cancomprise external flange 107 which can facilitate sealing fire doorassembly 100 to a floor or other surface. As shown in FIG. 3, frame 104can further comprise an internal flange 124, which functions as a stopfor door 104 when door 104 is in the closed configuration. Frame 102 canbe composed of any material suitable for use in fire door applicationincluding, for example, metals, metal alloys and combinations thereof,to provide desired levels of mechanical strength. In one embodiment,frame 102 can comprise aluminum, however, one of ordinary skill in theart will recognize that any metal suitable for use in fire doorapplications may be used to form frame 102.

Generally, door 104 is sized to fit into frame 102 and occlude opening108. Thus, the size and cross-sectional shape of door 104 can be guidedby the corresponding size and cross-sectional shape of frame 102. Asshown in FIG. 3, a gasket 126 can be connected to top member 110 to sealdoor 104 to internal flange 124 when door 104 is in the closedconfiguration. Gasket 126 can be composed of any material such as, forexample, fiberglass or the like, suitable for use in fire doorapplications. Door 104 can further comprise a latch system whichfunctions to secure door 104 to frame 102 when door 104 is in the closedconfiguration. In one embodiment, latch system can comprise latches 127connected to a central member 129 by cables (not shown). Latches 127generally comprise retractable protrusions which engage frame 102 in theclosed configuration. In some embodiments, to release latches 127,central member 129 can be rotated, which actuates the cables attached tothe latches 127 such that the protrusions can be retracted and door 104can be moved into the open configuration. Generally, central member 129is connected to a release handle located on top surface 111 of door 104such that the rotation of central member 129 can be accomplished byactuating the release handle. Additionally, top member 110 can compriseone or more handles which facilitate manually moving door 104 into theopen or closed configuration. Top member 110 can be composed of anymaterial suitable for use in fire door application including, forexample, metals, metal alloys and combinations thereof, to providedesired levels of mechanical strength. In one embodiment, top member 110can comprise aluminum.

As described above, first layer of insulation material 114 can be heldin a fixed position relative to top member 110 by support structure 112.As described below, the support structure is generally designed suchthat the support structure does not directly contact door frame 102 whendoor 104 is in the closed configuration. By eliminating contact betweendoor frame 102 and support structure 112, heat transfer from door frame102 to support structure 112, and ultimately to top member 110, can bereduced. Referring to FIGS. 3-4, support structure 112 can comprisesupport member 130, which is attached to and extends away from topmember 110 to provide structural support and rigidity to top member 110.Generally, support member 130 can comprise a plurality of structuralelements that are connected such that an internal door area 140 isdefined by support member 130. As shown in FIG. 4, support structure canalso comprise one or more cross bars 132 which can be connected tosupport member 130 and provide additional support and rigidity for topmember 110. In embodiments comprising a second layer of insulationmaterial, the second layer of insulation can be positioned in theinternal door area 140 between cross bars 132.

In some embodiments, support structure can further comprise an anglestructure or bracket 134 connected to support member 130. Generally, theangle structure provides as surface for mounting or connecting the firstlayer of insulation material 114 to the support structure that reducesthe contact points between the various components of the supportstructure. In one embodiment, angle structure 134 can comprise avertical component 136 and a horizontal component 138. In someembodiments, angle structure 134 can be formed by multiple elements thatare connected together, while in other embodiments angle structure 134can be formed by a unitary element that is formed into the desired shapeduring processing of the element. Vertical component 136 can beconnected to support member 130, while horizontal component 138 canprovide a surface for mounting the first layer of insulating material114 to door 104. As shown in FIG. 5, angle structure 134 can beconnected to support member 130 such that only six points of contact 142are established between angle structure 134 and support member 130. Infurther embodiments where the central angle bracket, shown exploded fromdoor 104 in FIG. 5, is not employed, only 4 points of contact existbetween angle bracket 134 and support member 130. Reducing the contactbetween angle structure 134 and support member 130 reduces the heattransfer pathways from angle structure 134 to support member 130, whichcan reduce heat transfer to top member 110.

As described above, door 104 can comprise first layer of insulationmaterial 114, which functions to reduced heat transfer from the bottomsurface 116 of door 104 to the top surface 111. In some embodiments,bottom surface 116 of door 104 can be formed by the first layer ofinsulation material 114, while in other embodiments bottom surface 116can be formed by, for example, a metal sheet or the like attached tofirst layer of insulation material 114. As shown in FIGS. 2 and 3, firstlayer of insulation material 114 can be formed by coupling a pluralityof insulation layers 128 together to form a composite insulationstructure. Generally, adding additional layers of insulation reduces theheat flow from bottom surface 116 to top surface 111 during a fire. Inone embodiment, insulation layers 128 can be coupled together by, forexample, a plurality of mechanical fasteners 131. Mechanical fasteners131 can be any fasteners suitable for use in fire door applications suchas, for example, metal screws, metal pins, and the like. In someembodiments, mechanical fasteners 131 can be aligned such that nocontact exists between fasteners 131 and support member 130, whichreduces potential heat transfer pathways through first layer ofinsulation material 114.

As shown in FIG. 3, in embodiments where the first layer of insulationmaterial 114 is composed of a plurality of layers 128 of insulation, thelayer of insulation closest to top member 110 can be directly connectedto horizontal component 138 of angle structure 134 by fasteners 142.Additionally, fasteners 142 can be covered by additional layers 128 ofinsulation material, which can insulate fasteners 142 and reduce heatflow to angle structure 134. Reducing the heat flow through fasteners142 to angle structure 134 can reduce the overall heat transfer to topsurface 111 of door 104. Furthermore, as shown in FIG. 3, fastener 142can also be insulated from heat by a layer of cement 144, or other floormaterials, which can surround frame 102 and extend under frame 102. Byextending cement layer 144 under fastener 142, and angle structure 134,cement layer 144 can provide additional insulation for angle structure134, which can reduce heat transfer to top member 110. In embodimentswhere first insulation layer 114 comprises a plurality of layers 128,the portion of cement layer 144 that extends under fastener 142 cancontact first insulation layer 114 and provide support to reduce theformation of gaps and/or seams between layers 128 during fireconditions. Extending cement layer 144 under fire door assembly 100 canalso provide a barrier between frame 102 and potential heat and fire,which can insulate frame 102 and reduces heat transfer to frame 102 anddoor 104. As shown in FIG. 3, when door 102 is in the closedconfiguration, first layer of insulation material 114 can contact frame102. Thus, the design of support structure 112 prevents direct contactbetween door frame 102 and support structure 112, which can reduce heattransfer from frame 102 to door 104.

First layer of insulation material 114 can be composed of any materialsuitable for use in fire door applications. Suitable materials include,for example, endothermic blanket materials composed of ceramic fibershaving bound water molecules located within the ceramic fibers,non-woven mineral fibers, non-woven mineral fibers impregnated withfiberglass, fiber board and combinations thereof. Preferred endothermicblanket materials are sold by 3M under the trademark Interam™. In oneembodiment, first layer of insulation material 114 can comprise Interam™E-5A material. In some embodiments, first layer of insulation material114 can be a composite structure comprising 1-6 layers of insulationmaterial, while in other embodiments first layer of insulation material114 can comprise 2-4 layers of insulation. One of ordinary skill in theart will recognize that additional layers of insulation material arecontemplated and are within the scope of the present disclosure. In someembodiments, all of the layers 128 of insulation material coupled toform first layer of insulation 114 can be the same type of insulationmaterial, while in other embodiments the layers 128 of insulation can bedifferent types of insulation. One of ordinary skill in the art willrecognize that the number and type of insulation coupled to form firstinsulation layer 114 can be guided by the intended application anddesired fire rating of a particular fire door assembly.

In some embodiments, door 104 can further comprise second layer ofinsulation material 122 oriented towards the top surface 111 of door104. Second layer of insulation material 122 provides additionalinsulation for top member 110 and reduces heat transfer to top surface111 of door 104. In some embodiments, second layer of insulationmaterial can be connected to top member 110 by, for example, mechanicalfasteners, adhesives or combinations thereof. Second layer of insulationmaterial 122 can be any material suitable for use in fire doorapplications including, for example, intumescent materials, endothermicblanket materials, non-woven mineral fibers impregnated with fiberglass,fiber board, mineral wool or combinations thereof. In one embodiment,second layer of insulation material can be composed of a 3M® duct wrapmaterial comprising non-woven mineral fibers impregnated withfiberglass. As shown in FIG. 3, support structure 112, which cancomprise support member 130 and angle structure 134, can hold firstlayer of insulation material 114 in a fixed position relative to secondlayer of insulation material 122 such that a gap 124 exists betweenfirst layer of insulation material 114 and second layer of insulationmaterial 122. Gap 124 can reduce heat transfer to top member 110 sincethe air, or other gasses, located in gap 124 can absorb heat.

As described above, multi-story buildings such as, for example, hotels,office towers, apartment buildings and the like are subject to specificfire related building codes and regulations. As a result, the floors,doors, ceilings and other structures must generally pass specific fireratings. Additionally, openings are generally present in multi-storybuildings to provide access and/or ventilation between floors. Theseopenings can allow a fire to spread between adjacent floors, andtherefore building codes and regulations generally require theseopenings to be occluded with fire rated materials. The fire doorassemblies described above can be used to occlude such openings betweenfloors in hotels, office towers and the like. The fire door assembliesof the present disclosure comprise structure to reduce heat transferbetween the frame and the door, which can reduce potential heat transferbetween adjacent floors in a multi-story building. Furthermore, thecombination of two layers of insulation material, along with a gapbetween the two layers, also can reduce heat flow between adjacentfloors of a building.

The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the claims. Although the presentinvention has been described with reference to particular embodiments,workers skilled in the art will recognize that changes may be made inform and detail without departing from the spirit and scope of theinvention.

1. A fire rated floor door assembly comprising: a door frame comprisingstructural elements defining an opening; a door sized to fit into theframe and occlude the opening, the door comprising: a top memberconfigured to have a selected orientation in a closed configuration withthe door engaging the frame; a first layer of insulation materialpositioned along the bottom surface of the door; and a support structureconnected to the first layer of insulation to hold the first layer ofinsulation in a fixed position that is spaced apart relative to the topmember, wherein the first layer of insulation material engages the framein the closed configuration without any contact between the supportstructure and the frame.
 2. The fire rated floor door assembly of claim1 wherein the support structure comprises a support member attached toand extending away from the top member.
 3. The fire rated floor doorassembly of claim 2 wherein the support structure further comprises anangle structure having a horizontal component and a vertical component,wherein the vertical component is connected to the support member. 4.The fire rated floor door assembly of claim 3 wherein the first layer ofinsulation material is connected to the horizontal component of theangle structure.
 5. The fire rated floor door assembly of claim 1wherein the first layer of insulation material comprises a plurality oflayers of insulation coupled together.
 6. The fire rated floor doorassembly of claim 5 wherein the layer of insulation closest to the topmember is connected to the support structure.
 7. The fire rated floordoor assembly of claim 5 wherein the plurality of layers are coupledtogether by a plurality of fasteners, wherein the fasteners are alignedsuch that no contact exists between the plurality of fasteners and thesupport structure.
 8. The fire rated floor door assembly of claim 1wherein the first layer of insulation material is selected from thegroup consisting of an endothermic blanket material comprising ceramicfibers having bound water molecules located within the ceramic fibers,non-woven mineral fibers, non-woven mineral fibers impregnated withfiberglass, fiber board and combinations thereof.
 9. The fire ratedfloor door assembly of claim 8 wherein the endothermic blanket materialcomprises Interam™ E-5A material.
 10. The fire rated floor door assemblyof claim 1 wherein the door further comprises a top surface and whereina second layer of insulation material is oriented towards the topsurface.
 11. The fire rated floor door assembly of claim 10 wherein thesecond layer of insulation material is selected from the groupconsisting of intumescent materials, endothermic blanket materials,non-woven mineral fibers impregnated with fiberglass, fiber board,mineral wool, and combinations thereof.
 12. The fire rated floor doorassembly of claim 11 wherein the non-woven mineral fibers impregnatedwith fiberglass comprise a 3M® duct wrap material.
 13. The fire ratedfloor door assembly of claim 10 wherein the support structure holds thefirst layer of insulation in a fixed position relative to the secondlayer of insulation such that a gap exists between the first layer ofinsulation and the second layer of insulation.
 14. The fire rated floordoor assembly of claim 1 wherein the frame comprises aluminum, an alloyof aluminum or a combination thereof.
 15. The fire rated floor doorassembly of claim 1 wherein the top member comprises aluminum, an alloyof aluminum or a combination thereof.
 16. The fire rated floor doorassembly of claim 1 wherein the bottom surface of the door is formed bythe first layer of insulation material.
 17. The fire rated floor doorassembly of claim 1 further comprises a layer of cement surrounding andextending under the door frame such that the cement layer insulates thesupport structure.
 18. A fire rated floor door assembly comprising: adoor frame comprising structural elements defining an opening; a doorsized to fit into the frame and occlude the opening, the door having atop surface and a bottom surface, the door comprising: a first layer ofinsulation material oriented towards the bottom surface of the door; asecond layer of insulation material oriented towards the top surface ofthe door; and a support structure connected to the first layer ofinsulation material to hold the first layer of insulation material in afixed position relative to the second layer of insulation material suchthat a gap exists between the first layer of insulating material and thesecond layer of insulating material.
 19. The fire rated floor doorassembly of claim 18 wherein the top surface of the door is formed by atop member.
 20. The fire rated floor door assembly of claim 19 whereinthe support structure comprises a support member attached to andextending away from the top member.
 21. The fire rated floor doorassembly of claim 20 wherein the support structure further comprises anangle structure having a horizontal component and a vertical component,wherein the vertical component is connected to the support member. 22.The fire rated floor door assembly of claim 21 wherein the first layerof insulation material is connected to the horizontal component of theangle structure.
 23. The fire rated floor door assembly of claim 21wherein a layer of concrete surrounds and extends under the frame suchthat angle structure is insulated by the layer of concrete.
 24. The firerated floor door assembly of claim 18 wherein the first layer ofinsulation material comprises a plurality of layers of insulationcoupled together.
 25. The fire rated floor door assembly of claim 18wherein the first layer of insulation material is selected from thegroup consisting of an endothermic blanket material comprising ceramicfibers having bound water molecules located within the ceramic fibers,non-woven mineral fibers, non-woven mineral fibers impregnated withfiberglass, fiber board and combinations thereof.
 26. The fire ratedfloor door assembly of claim 25 wherein the endothermic blanket materialcomprises Interam™ E-5A material.
 27. The fire rated floor door assemblyof claim 18 wherein the second layer of insulation material is selectedfrom the group consisting of intumescent materials, endothermic blanketmaterials, non-woven mineral fibers impregnated with fiberglass, fiberboard, mineral wool and combinations thereof.
 28. The fire rated floordoor assembly of claim 27 wherein the non-woven mineral fibersimpregnated with fiberglass comprise a 3M® duct wrap material.
 29. Thefire rated floor door assembly of claim 18 wherein the door framecomprise a metal, a metal alloy or a combination thereof.
 30. The firerated floor door assembly of claim 18 wherein the bottom surface of thedoor is formed by the first layer of insulation material.
 31. A methodof reducing the spread of fire through an opening comprising: providinga fire door assembly sized to occlude the opening, wherein the fire doorassembly comprises a door frame and a door, and wherein the doorcomprises a first layer of insulation material connected to a supportstructure such that the no contact exists between the support structureand the frame when the door is in a closed configuration.
 32. A firerated door assembly comprising: a door frame adapted to fit onto a floorsurface, the door frame having structural elements defining an opening;a door sized to fit into the frame and to selectively occlude theopening, the door comprising a top surface, a bottom surface and anendothermic blanket material positioned along the bottom surface of thefire door to reduce heat transfer from the bottom surface to the topsurface.